Do you mean you made a part refund? If so you get no refund of fees.
If you mean you made a FULL refund then there is a proper way to do this and that is through a case opened by the buyer. If you have just refunded in full thenyou still pay the selling fee and get a Defect.
Of course you can relist, look in MORE ACTIONS on the right side of your sold items page. As an alternative you can use SELL SIMILAR, you just have to make sure the details are correct.
